Goulds Pumps 3171 - IOM - Manual (Page 14)

Product Description
General description
Product description
The 3171 is a vertical submerged bearing sump and process pump.
This model is based on three bearing frames with 17 hydraulic sizes. The S/ST group has identical
bearings with a slightly different shaft on the impeller end for the S and ST. The M/MT group is identical
in all aspects for the power end. However, the liquid end of the MT is common with the S group except
that the MT is modified to accept a larger shaft. There are two MT sizes that are common with the S/ST
group.
This table shows the number of hydraulic sizes available for each drive-unit size group. Note that each
pump has a choice of two different discharge pipes which results in four combinations.
Drive-unit size group Number of hydraulic sizes
S/ST 9
M/MT 8
L 2
Casing
The casing has these features:
• A tangential discharge
• Is self-venting
• Has an integral bearing retainer
• Is precision-bored in order to ensure permanent alignment between the column casing, suction cover,
and bearing
Impeller
The impeller is fully-open, keyed to the shaft, and held in place by a self-locking capscrew in order to
ensure positive locking and prevent damage from reverse rotation. Impellers are spin-balanced (single
plane) to ISO G6.3. The impeller is provided with back vanes in order to reduce the axial thrust and
prevent the entrance of solids.
The impellers on this pump do not meet the dimensional requirements for dynamic balancing.
Strainer
The flat plate strainer is designed to maximize draw-down in a given sump depth. Openings are sized to
prevent the entrance of large solids that are commonly found in open sumps.
Discharge elbow
The discharge elbow is designed to allow the pump to fit into the smallest possible opening. A threaded
connection to the discharge pipe allows the pipe to be changed without removing the pump from the sump.
Column pipe
The column pipe has flanged connections that are machined in order to ensure true parallelism and to
maintain steady bearings concentric with the shaft.
Shaft
The standard design uses a one-piece shaft in order to ensure accurate alignment. The shaft is precision-
ground, polished, and straightened to keep vibration and deflection to a minimum. Standard bearing spans
keep the shaft well below first critical speed for all sizes.
Product Description
12 Model 3171 Installation, Operation, and Maintenance Manual